I’ve run into this exact issue after a big hailstorm a couple years back. Homeowner had a second layer put on about five years prior, thinking it’d be a quick fix after some wind damage. When we finally did a full tear-off, the decking underneath was a mess—rot, mold, even some spots where the nails had rusted clean through. The second layer just didn’t let the roof breathe, especially in our muggy Midwest summers.
I get why folks want to save money upfront, but in my experience, you’re just kicking the can down the road. That said, I’ve seen a few cases where a second layer held up fine for a decade or more, usually on steeper roofs with good attic ventilation. Still, it’s a gamble. If you’re in a spot with heavy rain or humidity, or if your roof’s already seen some storm action, I’d lean toward full removal. You get to check for hidden damage and upgrade insulation if needed. It’s not cheap, but neither is fixing water damage later...
That’s kind of what I’m worried about, honestly. We’ve got a 20-year-old roof with some missing shingles after last spring’s storms, and a couple contractors suggested just adding another layer to save on costs. But hearing about the hidden rot makes me nervous. Did you notice any signs inside the house before you tore everything off—like leaks or musty smells? Or was it all hidden until you opened things up? I keep checking the attic but can’t really tell if there’s a problem yet...
That’s exactly what had me second-guessing the “just add a layer” route, too. I kept thinking it’d be cheaper, but then I started reading about how you can trap moisture and never know until it’s way worse. In my case, there weren’t any obvious leaks inside—no brown spots on the ceiling or anything like that. The attic always seemed dry, but there was this faint musty smell I couldn’t quite place... not strong, just kind of lingering after rain.
When we finally bit the bullet and did a full tear-off (asphalt shingles, midwest climate, lots of freeze/thaw), we found a couple patches of rotten decking right above where some shingles had blown off. It wasn’t visible from inside at all. The insulation looked fine, no drips or stains—just that weird smell sometimes. I guess what surprised me was how localized the damage was; if we’d just gone over it, it probably would’ve gotten worse and maybe even spread.
I get why contractors suggest the extra layer—it’s faster and cheaper up front—but I’m not convinced it actually saves money long-term if you end up with hidden rot or ventilation issues. Plus, two layers means more weight on your rafters, which isn’t ideal for older houses.
Are your missing shingles mostly in one area or scattered all over? And what kind of shape is your attic ventilation in? I’ve heard poor airflow can make hidden moisture problems way worse, especially with multiple shingle layers. Sometimes it’s hard to tell if there’s an issue until you open things up... but maybe there are other signs I missed?
That musty smell is exactly what made me nervous, too. I kept telling myself it was probably nothing, but after hearing stories like yours, I’m glad I didn’t just slap another layer on. My place is older and I’ve got a few missing shingles in one corner, but the attic looks fine—no stains or anything. Still, I keep wondering if there’s something hiding under the surface. The weight thing freaks me out a bit, too, since my rafters already creak when it’s windy. It’s tough to know what’s really going on up there without ripping things open, but your experience makes me feel a little better about leaning toward a full tear-off, even if it’s pricier upfront.
That musty smell is always a red flag for me, especially in older homes. Even if you don’t see stains in the attic, moisture can hide in weird places—like between layers of old shingles or under felt that’s been there for decades. I had a similar situation a few years back: no visible leaks, but when we finally did a tear-off, there was a patch of rotten decking right above a rafter. Never would’ve spotted it from inside.
The weight issue is real, too. My house was built in the 60s and the rafters aren’t exactly beefy. Adding another layer would’ve pushed things past what I was comfortable with, especially with snow loads in winter. Have you had anyone actually check the rafter sizing or look for sagging from outside? Sometimes you can spot a slight dip along the ridge or eaves if things are overloaded.
Curious if you’ve looked into what your local code says about layering roofs? In my area, you can only have two layers max, but some inspectors are stricter if the structure’s questionable.